Generally, plural pieces of guide bar blades 10 shown in FIG. 1 and not less than two guide bars incorporated into a frame 32 shown in FIG. 2 are installed into an automatic loom. More strict wear resistance has become required for loom guide bar blades used for an air jet loom or a water jet loom with the recent speed-up of such automatic looms. Heretofore, a material such as metastable austenitic stainless steel, remarkably superior in work hardening, or ferritic stainless steel, wherein the surface is hard-plated, has been employed as a material for the above guide bar blades in order to maintain corrosion resistance as well as the above wear resistance.
However, recently, further speed-up of weaving machinery has been promoted. The above materials involve a problem from the viewpoint of wear resistance in promoting the further speed-up. Namely, a Vickers hardness of about 500 Hv is the limit in improving the hardness of metastable austenitic stainless steel by work hardening. Since the above material cannot withstand high-speed rotation of a loom, for example, not less than 500 r.p.m. (revolutions per minute), and is worn away greatly, the yarn fluffs in a short time, which causes the difficulty in continued weaving. However, to improve surface hardness, for example, TiN coating by physical vapour deposition (PVD) or hard chromium plating is available. Although these plating methods can provide sufficient surface hardness, on the other hand, the methods involve a problem in that a coating or plating can easily peel due to the flexibility of guide bar blades since the adhesiveness of the base materials to the above coatings or platings is not sufficient.
In the meantime, a carbo-nitrided iron material easily rusts as same as the above stainless steel in case of being frequently exposed to water projection, for example, in a water jet loom. As a result, yarn passing through guide bar blades discolors so that this material is not suitable to make guide bar blades therefrom.